When I apply my brakes at rest for any length of time, at a
stoplight for instance, I eventually hear a hiss that is usually
accompanied by the brake pedal slowly sinking toward the floor. If
I pump the brake pedal it goes back to the top without issue.
While troubleshooting and looking for the source of what I
suspected is a vaccuum hose leak, I noticed that the fluid
reservoir feeding the master brake cylindar is low, while the fluid
resevoir feeding the slave brake cylindar is too high, to the
extent that fluid has started to be forced out of the top of the
reservoir. So somehow fluid is being transferred from one
reservoir to the other.
What is going on? Do I have multiple problems, or do I just need
to rebuild (replace?) my slave cylindar - or some other such fix?
Do I have a vaccuum issue?–
Charlie 1967 XKE 2+2
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from CGivans sent Tue 11 Oct 2011:
Charlie, It looks as if you are in for a rebuild of the
servo, because the rubber pistons are leaking fluid, either
because they are just old, OR ( and a lot more likely) the
bore of the servo has some (micro)pits in it…meaning you
need to do a resleeve and rebuild or buy a new one, which
ever best suits you!! You will find lots about this in the
archives, which you will access under’’ search forms )…the
brown-ish tab upper right 4 lines below the pictures.–
The original message included these comments:
suspected is a vaccuum hose leak, I noticed that the fluid
reservoir feeding the master brake cylindar is low, while the fluid
resevoir feeding the slave brake cylindar is too high, to the
extent that fluid has started to be forced out of the top of the
reservoir. So somehow fluid is being transferred from one
reservoir to the other.
Charlie 1967 XKE 2+2
–
John M Holmes 1973 E Type SIII Supra 5Sp, 70 SII OTS 05XJ8L
Ontario, Canada
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from John M Holmes sent Tue 11 Oct 2011:
Yup. Had exactly the same experience years ago. For confirmation,
when you take apart the vacuum servo you’ll find brake fluid in the
diaphragm where it’s leaking past the seal. All it took in my case
was a rebuild kit. You’ll notice better braking afterward.–
The original message included these comments:
Charlie, It looks as if you are in for a rebuild of the
servo, because the rubber pistons are leaking fluid, either
because they are just old, OR ( and a lot more likely) the
In reply to a message from CGivans sent Tue 11 Oct 2011:
Thanks.
Checked the archieves, and agree that a rebuild/replacement of the
servo is in order. What a great forum!
Will this also fix the hissing sound that occurs and sounds like a
vaccuum leak, or is that likely another issue?–
The original message included these comments:
When I apply my brakes at rest for any length of time, at a
stoplight for instance, I eventually hear a hiss that is usually
accompanied by the brake pedal slowly sinking toward the floor. If
In reply to a message from CGivans sent Tue 11 Oct 2011:
I’m assuming your vacuum hoses are in good shape and they are well
clamped in the six locations where they connect within the system.
It is also likely the servo diaphragm is perforated or cracked from
age, but you’ll be able to determine that when you take it apart.
Worth replacing in any event. Once you have the system rebuilt the
hissing sound will disappear.–
The original message included these comments:
Will this also fix the hissing sound that occurs and sounds like a
vaccuum leak, or is that likely another issue?